Computer tomography devices (CTs), serve to make three-dimensional images or images of slices through a body to be examined. The image data are obtained by means of X-radiation, using an X-ray beam source that rotates on a circular path around the body to be examined. An X-ray detector rotates jointly with the X-ray beam source, but diametrically opposite to the beam source, and detects the raw image data.
The raw image data represent two-dimensional X-ray projections with many different projection directions, corresponding to the rotation. From the two-dimensional X-ray projections, slice images or three-dimensional X-ray images are generated by a computer.
The quality of the X-ray images that can be generated depends substantially on the stable, exact position of the body to be examined. Deviations in the position of the body from the optimal position in the CT and changes in the body position during the time-consuming acquisition of the X-ray image data impair the quality of the resultant images.
To be able to assure the stable and exact positioning of the body of the patient in the CT, a device for supporting a patient is provided. A CT has a so-called “gantry”, inside of which the X-ray beam source and the X-ray image detector rotate. At the center of rotary motion, the gantry has an opening, in which the patient is positioned for the acquisition of the raw image data. The device for supporting a patient serves to slide a patient, supported on the supporting device, into the opening in the gantry.
The supporting device is sufficiently stable to be able to bear the weight of the patient, and sufficiently movable to enable positioning the patient inside the gantry.
However, sagging of the device for supporting a patient or of a stretcher placed on the supporting device from the weight of the patient cannot be avoided. Such sagging may be reduced by means of additional structural provisions, such as additional braces.
The device for supporting a patient is intended to allow placing the patient or the stretcher along with the patient onto it without problems. To that end, the supporting device should be movable in many directions and in particular should be capable of being lowered quite far, so that a patient being placed on it or shifted to the supporting device need not be lifted. On the one hand, this puts less of a burden on the medical staff. On the other, this also is beneficial to the patient, for whom, depending on physical condition, the shifting can be unpleasant and painful. Especially when a patient is being examined by more than one kind of medical equipment, such as a CT as well as a C-arch X-ray machine, the frequent shifting from one machine to another is a great burden and entails great effort.
German Patent Disclosure DE 101 08 549, teaches supporting a patient on a stretcher that can be moved by a so-called trolley, or movable carriage. To make a CT scan, the stretcher is placed on a fixed base, located in front of the gantry of a CT, with which the stretcher can be introduced into the gantry and removed again. The fixed base assures stable positioning of the patient, but does not offer any further motion capabilities.